need stock front wheel back spacing on 68 gts??15x6s/7s up front?? or 14"

having a set of custom wheels built and they want to know what the factory back spacing is i guess on my 14" rims even thou im going with 15x6 there trying to talk me into 15x7 up front seem a littel to much any one have input
i just want a wheel to cover my disc breaks ill run my 14s if most kits clear it
if i have to spend the 200 on new wheels and then the 100 for paint i will but y bother if i dont have to


chubs